In order to accommodate the rigors of applications within large-scale equipment, providing reliable and durable large-scale sealing solutions has become of key importance in various industries. For example, in the offshore industry, the drilling into ever-deeper water brings with it numerous technical challenges, related to both equipment and operations, in particular for high-performance sealing systems. The sealing systems should be able to accommodate the large dimensions of the offshore equipment, combined with pressure, force and/or temperatures of the deep water environment. For deep water applications, the sealing systems in the offshore industry should be able to withstand high pressures, for example pressures amounting up to 500 bar. The diameter of the seals may vary between for instance 20 cm and several m.
The sheer scale of the equipment often requires sealing systems that allow in-situ servicing, with only partial disassembly. Tailored sealing solutions are required to mitigate for such requirements.
A method of forming large diameter thermoplastic seals is for example described in US2010/0116422 A1. US2010/0116422 A1 discloses the steps of heating an extruded rod, bending the heated extruded rod, joining the ends of the extruded rod to form a semi-finished ring, and annealing the semi-finished ring. The semi-finished ring may be machined or further processed to form a seal ring, back-up ring, or other seal device. In an example, joining the ends of the extruded rod includes welding the ends of the extruded rod by melting the ends and pressing the ends together. In particular, heating the extruded rods includes heating the rods to a temperature greater than the glass transition temperature. For most thermoplastic materials, this temperature is larger than 120° C. and requires a dedicated healing system to be installed and adjusted to the size of the extruded rods. In addition, the semi-finished ring resulting from the heating, bending and joining the ends of the extruded rod, needs further machining in order to obtain a finished seal. This method may be considered to be rather complicated and it does not allow in-situ forming of a sealing element, which is considered desirable in many sealing systems used in the offshore industry.